For many viruses, the prevalence of infection in the general population is very high. Viruses of the herpesviridae family, such as herpes simplex virus, varicella zoster virus and Epstein Barr virus, are all viruses that infect a large proportion of the population on a regular basis. In some cases, the majority of the population will be infected during their lifetime.
For example, in the case of herpes simplex virus type 1 (HSV-1), the virus infects 40 to 60% of teenagers and young adults, and over 90% of the population by 60 years of age. This virus commonly infects the circumoral regions, both inside and outside the mouth. The natural course of the illness ranges from 10 days to 4 weeks, dependent on the extent of infection and the host status. Common clinical manifestations of HSV-1 infection are primary herpetic stomatitis and recurrent herpes labialis.
Herpes simplex type 2 (HSV-2) is the commonest causal agent for herpetic genital infections. It is estimated that 10% of the population in Western countries have genital herpes, but that only 20 to 25% of infected individuals are aware of their condition.
Herpes Zoster is a recurrent infection of the varicella-zoster virus (chickenpox virus) and has an incidence of 0.4 to 1.6 cases per 1000 among healthy people less than 20 years of age, rising to an incidence of 4.1-11.0 per 1000 for people greater than 80 years of age. The virus causes a wide range of problems affecting the skin and the eye. After the initial infection (chicken pox), the virus lays dormant in nerve cells and then becomes reactivated as a result of many factors such as aging, stress, suppression of the immune system, and certain medications.
Oral hairy leukoplakia (OHL) is an oral mucosal disease. It is due to infection by Epstein-Barr virus (EBV) and occurs most commonly in subjects who are immunocompromised, particularly those infected with HIV.
For most of these viruses, there is no effective treatment once infection has occurred. Oral and/or topical antivirals such as acyclovir, famciclovir and valcicovir are often prescribed with herpes simplex and herpes zoster infections, or for the treatment of oral hairy leukoplakia. However, the efficacy of such agents is often limited. In addition, such agents often require an extended treatment regime and the timing of commencement of treatment can determine its efficacy. For example, in the case of HSV-1 and HSV-2 lesions, it is recommended that treatment is started within 1 hour of prodrome, while for Herpes Zoster, treatment should be started within 72 hours of signs of rash.
The current treatment of herpesviridae infections is inadequate for many reasons. Accordingly, there is a need for new compositions and methods that have the capacity to inhibit such infections.
The present invention relates to the use of extracts from plants in the Asteraceae family to inhibit infection by viruses in the herpesviridae family, and the use of the extracts to provide relief from such infections.
A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims.